Silence. Last September, when I visited a makeshift hospital in Adré, Chad, where young Sudanese refugees were being treated for acute malnutrition, that was all I heard: an eerie silence.

I had tried to prepare myself for the wails of children who were sick and emaciated, but these patients were too weak to even cry. That day, I saw a 6-month-old baby who was the size of a newborn and a child whose ankles were swollen, and whose body was blistered, from severe malnourishment.

It was equal parts newly horrific and tragically familiar.

Twenty years earlier I had visited the same town and met with Sudanese refugees who fled violence in Darfur, where the Janjaweed, with backing from Omar al-Bashir’s brutal authoritarian regime, carried out a genocidal campaign of mass killing, rape and pillage.

Today, civil war has once again turned Sudan into a living hell. But even after aid groups designated the country’s humanitarian crisis to be among the world’s worst, little attention or help has gone to the Sudanese people.

For almost a year, I have been pushing the United Nations Security Council to speak out. On March 8, the Council finally called for an immediate cessation of hostilities. This is a positive step forward, but it is not nearly enough — and it does not change the fact that the international community and media outlets have been largely quiet.

The world’s silence and inaction need to end, and end now.

The first thing that must happen is we must surge humanitarian support to Sudan’s most vulnerable. Eighteen million Sudanese face acute hunger, and famine is looming. Nearly eight million people have been forced from their homes in what has become the world’s largest internal displacement crisis. Measles, cholera and other preventable diseases have spread.